In many color adjustment algorithms, input RGB color values are commonly adjusted outside of the device gamut. These color values must be mapped back to in-gamut colors in order to be processed by the printing device. Gamut clipping is a common method which is often used to accomplish this objective. In one gamut clipping method, each RGB channel is clipped to a range between [0,1]. Such a method is simple and efficient but can produce undesirable hue shifts and posterization. Posterization is a process in photograph development which converts normal photographs into an image consisting of distinct, but flat, areas of different tones or colors. Posterization of an image occurs when a region of an image with a continuous gradation of tone is replaced with several regions of fewer tones, resulting in an abrupt change from one tone to another. A posterized image often has the same general appearance, but portions of the original image that presented gradual transitions are replaced by abrupt changes in shading and gradation from one area of tone to another. On the other hand, more elaborate gamut mapping algorithms are known but these generally operate in L*a*b* space which involves an increase in computational complexity and increased processing.
Accordingly, what is needed in this art are increasingly sophisticated systems and methods for mapping out-of-gamut RGB colors to a gamut surface which avoids the posterization problems often associated with gamut clipping.